1. Technical Field
The present invention relates to wire terminal blocks, and more particularly to a terminal block assembly where electrical leading wires are inserted and connected. The inventive terminal block assembly features for a combination of a lever member, a buckle and a metal spring piece that can be operated in an effort-saving manner to crimp or release a leading wire inserted into the terminal block assembly.
2. Description of Related Art
A terminal (block) or a crimp terminal (block) using a metal piece or a metal spring piece covered by an insulating housing (typically made of plastic) to crimp a leading wire inserted therein and thereby form electrical connection is known.
Such a connecting terminal designed be inserted onto a circuit board (such as a PC circuit board) has an insulating housing that is provided with a through hole or an wire inlet, through which a leading wire can be inserted to the interior of the housing. The housing defines therein a chamber for receiving a metal spring piece as described previously, so as to form contact or electrical connection with the leading wire inserted into the housing. The metal spring piece has a head, serving to crimp the leading wire inserted into the housing so as to prevent the leading wire from disconnecting form the metal spring piece or leaving the insulating housing. The established connection between the leading wire and the metal spring piece can be only dismissed when the head is pushed by a tool accessing it from the exterior of the housing.
Basically, the metal spring piece is connected to a terminal pin that is formed symmetrical and narrow, so as to be inserted onto and become electrically conductive with the circuit board.
The prior art also discloses an approach to controlling such a metal spring piece to crimp or release a leading wire by providing a terminal block or a connecting terminal with a lever member. For example, a prior art has proposed a reasonable embodiment, wherein a metal spring piece spans over two sides of a lever member with a forked head, for bearing and responding to operation of the lever member. In other words, when the lever member is operated to press the metal spring piece downward, it forces the tail of the metal spring piece to go downward and engage with a leading wire inserted into the terminal block. When the lever member is operated oppositely, its end pushes the forked head of the metal spring piece in the manner that the tail of metal spring piece raises and the crimped leading wire is now released.
In the foregoing prior art device, for ensuring that the tail of the metal spring piece can firmly secure the leading wire entering the terminal block without the risk of unintentionally disengagement, the forked head of the metal spring piece is provided with a curved segment and a pair of slender arms are extended from the upper portion of the terminal pin corresponding to the curved segment. When the lever member presses the metal spring piece's forked head, the curved segment is pushed toward and get grasped by or engaged with the arms. When the lever member is pushed upward, it drives the curved segment to get away from the arms, so as to dismiss the engagement and release the leading wire.
One issue about such a terminal block or connecting terminal in terms of structural design and application is that for endowing the curved segment with structural strength sufficient for the engagement with the arms of the terminal pin and thus preventing deformation that degrades the engagement between the metal spring piece and the leading wire over time, the curved segment in practice is made as a U-shaped structure. However, the specially processed structure can significantly increase the complexity and cost level for manufacturing the metal spring piece.
Another issue about such a terminal block or connecting terminal in terms of structural design and application is that for ensuring good electrical conductivity, the terminal pin is usually made of a metal material containing cooper (e.g. brass or the like) and thus is less rigid. This makes the terminal pin show inferior structural strength when its arms engage with the curved segment of the metal spring piece. Particularly, after long-term operation, the arms tend to deform and become unreliable for the intended engagement. While this problem may be solved by increasing the thickness or area of the arms, the consequent high complexity and costs are adverse to the relevant manufacturers.
Briefly, the aforementioned references do propose some ideas about the design and combination of connecting terminals/terminal blocks, lever members, metal spring pieces, and terminal pins. It is thus believed that by rearranging and recombining these components, a novel approach superior to the existing devices can be devised to improve the structure, structural strength, utility and thereby applications of a terminal block while minimizing the manufacturing cost and potential deformation.
Apart from overcoming the above-mentioned issues, a preferred terminal block shall satisfy some more expectancies. For instance, with the overall capability and reliability of the crimp and engagement ensured, it is preferred that the operation of the lever member is effort-saving. Also, it is preferred that the structural complexity of the terminal block, the lever member, the metal spring piece and the terminal pin is further improved. These have been neither mentioned nor disclosed in the previously discussed references.